Railway signaling



April 6, 1937. E. M. ALLEN RAILWAY SIGNALING 3 Sheets-Sheet 1 Filed Feb. 15, 1936 l R Y o E 3 Q W m MM? w a A E m m w 3% u aw m wbwfi N n m @QWWm m fi m; E w QL M e @Sw o 11 L" F at Fa mm m Nfiw Ewfi D N D Q Q Q i w 5% A] wmw T mfi BR NNAMNHT Emu NNA MN/XHF E. M. ALLEN RAILWAY SIGNALING 5 Sheets-Sheet 2 Filed Feb. 15, 1936 INVENTOR Earl M Allen.

BYQWJ HIS ATTORNEY April 6, 1937.

0 I A T1 kw WTTQ sm KN TS Q April 6, 1937. E. M. ALLEN RAILWAY SIGNALING s Sfieets-Sheet 3 Filed Feb. 15, 1936 n Q Q m WC a Nu mA. m w n m ENWW wm my E m L ,m a g m m w msqmm w o mm m A m D IUD QY I YW ML wmm m m @YL WN [I01 Raw A L x Q @L/r Rev Em U III b |L l Ill 1! @L Lm V [R MN L )1 mfiwm MEN al N W a NA RH Ail WTTQ kw WTTQ hm MW Patented Apr. 6, 1937 UNITED STATES PATENT OFFICE.

RAILWAY SIGNALING Application February 15, 1936, Serial No. 64,129

20 Claims.

My invention relates to railway signaling, and particularly to signaling involving wayside signals located along a trackway for governing the passage of trains.

A feature of my invention is the provision of novel and improved apparatus for establishing a distinctive control for each of five sections in the rear of an occupied section. Each distinctive control is effective to cause a corresponding 10 aspect of the associated wayside signal, whereby thereis produced a five block, six-indication, system" of signaling.

Another feature of my invention is the provi sion of novel and improved apparatus for con- 5 trolling the signals in such a manner that when one signal is displaying a restrictive indication, the signal for the section next in rear will display the same indication and will display a less restrictive indication only if a train consumes a predetermined amount of time in approaching such signal for the section next in rear.

I will describe several forms of apparatus embodying my invention, and will then point out the .novel features thereof in claims.

In the accompanying drawings, Figs. 1A and 1B are diagrammatic views which, when placed end to end in the order named, illustrate one form of apparatus embodying my invention. Figs. 2 and 3 are diagrammatic views illustrating modifications of a portion of the apparatus shown in Fig. 1B and each also embodying my invention.

Similar reference characters refer to similar parts in each of the several views.

Referring first to Figs. 1A and 1B, the reference characters 10 and i I designate the rails of a stretch of railway track along which traffic normally moves in the direction indicated by the arrows. These rails are divided by insulated joints I2 into a plurality of track sections 3T, 4T, 5T, 6T, IT, 8T, etc. Each section is provided with a track circuit which includes a track battery l3 connected across the rails at one end of the section and a track relay, designated by the reference character R with a prefix the same as the refer- 45 once character of the associated section, connected across the rails at the other end of the section.

To govern the passage of trains through the stretch of railway, a wayside signal, designated by a reference character the 'same as the numerical prefix in the reference character of the associated section, is provided for each track section. Each of these signals comprises an upper unit U and a lower unit L. These units may take any 55 one of several forms of signal mechanisms such as Searchlight, semaphore, color light, or position light. As here shown, each upper unit is a searchlight signal mechanism capable of display ing a red light, a yellow light, or a green light, and each lower unit L is a lamp, designated by the reference character LE with a prefix the same as the reference character of the associated signal. The lamps LE, as here shown, display a white light but may be arranged to display a colored light if desired.

The Searchlight signals may be such as described and claimed in United States Letters Patent No. 1,864,224, issued June 21, 1932, to W. B. Wells, for Light signals. For the purpose of this application, it is deemed sufiicient to but briefly describe these signals. Referring to signal 3, for example, it includes a pivotally mounted rotor MA controlled by a permanent magnet (not shown) and by an operating winding I4. Energization of the operating winding 14 with current of one polarity causes the rotor MA to be rotated in one direction moving the signal to the clear indication position; energization of the operating winding M with current of the reverse polarity causes the rotor MA to be rotated in the opposite direction to move the signal to the caution indication position; while deenergization of the operating winding 54 permits the rotor MA to be returned by gravity to a center position which is the stop indication position. Associated with the rotor I i-A is a signal lamp 3UE. As pointed out in detail in the aforementioned patent, when the rotor MA is rotated to the clear position, a green colored filter G is moved in front of the lamp BUE so that a green signal light will be displayed when lamp 3UE is lighted. When the rotor MA is rotated to the caution position, a yellow colored filter Y is moved in front of lamp SUE so that, with lamp 3UE lighted, a yellow signal light will be displayed. In like manner, the positioning of the rotor l lA in the center position moves a red colored filter R in front of lamp SUE so that a red signal light is displayed whenever lamp SUE is energized. The rotor MA actuates a set of circuit controlling contacts in such a manner that the contact l5-l ii is closed only in the clear indication position, contact l'l--l8 is closed only in the caution indication position, and contact [5-49 is closed both in the stop and caution indication positions. The lamp SUE may be constantly burning, as shown herein, or may be approach lighted in any usual and well-known manner.

Each upper and lower unit of the wayside signals functions in a manner similar to that described for the upper and lower units of signal 3.

From the foregoing description of the signals shown herein, it will be apparent that six distinctive indications may be displayed by various combinations of the upper and lower units of each signal. That is, the upper unit alone may provide three indications and the lower unit when displayed simultaneously with the upper unit may provide three additional and different indications. As will be pointed out more in detail hereinafter, when an upper unit is displaying a particular indication, the lighting of the lower unit will cause that signal to display a less restrictive indication. With this arrangement, it will be obvious that in the event the lamp in the lower unit should become burned out, the signal will automatically display a more restrictive indication. My system, therefore, requires no light-out relays or other apparatus to prevent the display of a less restrictive indication in the event a lamp of the lower unit should become burned out or otherwise fail to light at the proper time.

Each signal is provided with a signal control relay designated by the reference character LR with a prefix the same as the reference character of the associated signal. The signal control relays LR control the lower unit of the associated signal. For example, the lamp 3LE is controlled over a front contact 2d of the signal control relay 3LR so that lamp 3LE is lighted whenever relay 3LR is energized.

Each signal is provided with a clear indication repeating relay which is designated by the reference character DP with a prefix the same as the reference character of the associated signal and which is energized only when the upper unit of the associated signal is in its clear indication position. For example, the relay SDP is controlled over clear contact l5-l6 of the upper unit of signal 3 so that relay SDP is energized only when the upper unit U of signal 3 is in its clear position.

Each signal is provided with a pole changing relay having a slow release characteristic and which is designated by the reference character HDP with a prefix the same as the reference character of the associated signal. Each pole changing relay is energized when the associated repeating relay DP is energized, or when the associated upper unit is in its caution condition provided the associated signal control relay LR is then energized. For example, the relay 3I-IDP may be energized over a circuit which includes front contact 2! of the relay BDP or over another circuit which includes caution contact l'li8 of the upper unit of signal 3 and front contact 22 of signal control relay .iLR.

The operating winding Ml of each searchlight mechanism is connected to a signal line circuit governed by the pole changing relay I-IDP of the signal for the section next in advance and in cluding a front contact of the track relay for the associated section as well as a front contact of the track relay for such advance section. That is, operating windings M of the upper mechanisms may be energized by current of one polarity v or the other polarity depending upon the condiauxiliary line circuit one wire of which is also one wire of the signal line circuit for the upper unit of the signal with which such signal control relay is associated. The line circuit for each signal control relay LR includes a front contact of the track relay for the associated section and may be supplied by energy over a back contact of the signal control relay LR of the signal for the section next in advance, or may be supplied by energy over a front contact of the signal control relay LR for the signal in advance provided the clear repeating relay DP for such advance signal is then energized. That is, each relay LR iay be energized when the associated section is unoccupied either when the signal control relay LR for the signal next in advance is deenergized, or when the signal control relay LR for the signal next in advance is energized provided the upper unit U of such advance signal is then in its clear condition.

The polarity of the auxiliary line circuit for each signal control relay LR is controlled by the pole changing relay HDP for the signal in advance in such a manner that the polarity of the two line wires is always of the proper polarity. That is, the polarity of the current supplied to the line conductors at the auxiliary line circuit is so controlled that the common line conductor is always of a polarity opposite to the polarity of the other line conductor when such other conductor is energized.

Each of the signals herein shown is controlled by the associated signal control relays LR and operating windings Hi in the following manner: When the operating winding [4 and the signal control relay LR are both deenergized (see signal 3) the upper unit U of that signal will display a red light and the lower unit L will be extinguished. Signal 3, therefore, displays a single red light to indicate stop. When the operating winding i4 is deenergized and the relay LR is energized (see signal l) the upper unit U of that signal will display a red light and the lower unit L will display a white light. Signal 4, therefore, will display a red light over a white light to indicate prepare to stop at next signal. When operating winding [4 is energized in the reverse direction and the relay LR is deenergized (see signal 5), the upper unit of that signal will display a yellow light and the lower unit will be extinguished. Signal 5, therefore, will display a single yellow light to indicate approach next signal at slow speed. When the operating winding i4 is energized in the reverse direction and the relay LR is energized (see signal 6), the upper unit of that signal will display a yellow light and the lower unit will display a white light. Signal 6, therefore, displays a yellow light above a white light to indicate proceed at medium speed. When the operating winding M is energized in the normal direction and relay LR is deenergized (see signal 1), the upper unit of that signal will display a green light and the lower unit will be extinguished. Signal l, therefore, will display a single green light to indicate approach next signal at medium speed. When the operating winding I4 is energized in the normal direction and the relay LR is energized (see signal 8), the upper unit of that signal will display a green light and the lower unit will display a white light. Signal 8, therefore, will display a green light above a white light to indicate proceed at normal speed.

As shown in the drawings, the section ST is 00- cupied by a train K so that operating winding l of the upper unit of signal 3 and signal control relay 3LR are both deenergized, with the result that signal 3 displays a single red light to indicate n topn When signal 3 is displaying the stop indication, signal control relay 4LR is energized over a line circuit which passes from terminal B of a suitable source of energy, at signal 3, through back point of contact -23 of relay 3HDP, relay 411R, front contact 24 of track relay 4TB, back point of contact '25 of relay, and back point of contact "26 of relay 3HDP to terminal C of the same source of energy. Lamp tLE, therefore, is energized over front contact 2! of relay 411R to cause signal 5 to display a red light over a white 3 light.

back point of contact 3| of relay 4HDP to terminal C. Signal 5, therefore displays a single yellow light.

When signal 5 is displaying this indication, op-

erating winding [4 of the upper unit of signal 6 is energized in the reverse direction over a line circuit which passes from terminal B at signal 5, through back point of contact 32 of relay 5HDP, operating winding ll of signal 6, front contact 33 of track relay 6TH, front contact 34 of track relay 5TH, and back point of contact 35 of relay SHDP to terminal C; and relay SLR is energized over a line circuit which passes from terminal B, at signal 5, through the back point of contact 32 of relay EHDP, relay SLR, front contact 36 of track relay BTR, back point of contact 31 of relay ELR, and back point of contact 35 of relay BHDP. Lamp GLE, therefore, is energized over front contact 38 of relay SLR so that, with upper unit U of signal 6 energized in the reverse direction, signal 6 displays a yellow light over a white light.

When signal 6 is in this condition, the relay SI-IDP is energized by a circuit which passes from terminal B through caution and stop contact l5--|9 of signal 6, caution contact |'Il8 of signal 6, front contact 39 of relay BLR, and relay BI-IDP to terminal C.

When both relay GHDP and relay SLR are energized, operating winding M of the upper unit of signal I is energized in the normal direction over a line circuit which passes from terminal B at signal 6 through front point of contact 40 of reis deenergized, operating winding 54 of the upper unit of signal 8 is energized in the normal direction over a line circuit which passes from terminal B at signal 1, through front point of contact of relay lI-IDP, front contact 46 of relay 'FTR, front contact 41 of relay 3TB, operating winding M of signal 8, and front point of contact 48 of relay lI-IDP to terminal C; and relay BLR is energized over a line circuit which passes from terminal B at signal 1, through front point of contact 45 of relay THDP, back point of contact 49 of relay lLR, front contact 50 of track relay 8'I'R, relay 8LR, and front point of contact 48 of relay THDP to terminal C. Lamp 8LE, therefore, is energized over front contact 5| of relay BLR so that with the upper unit energized in the normal direction, signal 8 displays a green light over a white light to indicate proceed at normal speed.

When signal 8 displays the proceed at normal speed indication, the relay 8DP is energized over clear contact l5--l6 of signal 8 so that relay 3HDP is energized over front contact 52 of relay SDP.

Under this condition, that is, with both relay 8H1)? and relay BLR energized, the line circuit for the control of the upper unit for the signal next in rear (not shown) is supplied with energy of normal polarity over the front points of contacts 52 and 53 of relay BHDP, and the signal control relay (not shown) for such rear signal is energized over a circuit which includes front con tact 54 of relay BDP and front point of contact 55 of relay SLR as well as front point of contact 53 of relay BHDP. The signal (not shown) next in rear, therefore, also displays a green light over a white light which is the normal proceed indication.

Referring next to Fig. 2, it will be noted that section 2T (the section next in advance of section 3T) is shown together with the usual signal and associated apparatus. Signals 2 and 4 function in all respects in a manner similar to that described for the signals shown in Figs. 1A and 1B. The control for signal 3, however, has been modified somewhat. That is, as will be explained more in detail hereinafter, signal 3 displays the stop indication whenever section 2T is occupied as well as when sect-ion 3T is occupied; and, when section 2T is occupied, signal 3 can be caused to display a less restrictive indication only if a following train consumes a predetermined amount of time in section 4T. This arrangement provides for safer train operation particularly on down grades, in that a following train is required to stop at the second signal in rear of an occupied block if and only if such train exceeds the authorized speed in approaching such second signal. At the same time, this arrangement permits the following train to pass the signal without stopping if the speed of the train is properly controlled.

Furthermore, when section 2T is occupied, the first restrictive proceed indication will be dis played at signal I so that five clear sections are provided between signal 1 and the occupied section instead of four clear sections, as shown for the system shown in Figs. 1A and 1B. Additional braking distance, therefore, is provided so that heavy tonnage trains which may be unable to stop at signal 3 will be certain to stop before passing signal 2.

The reference character ZTE designates a normally deenergized timing device, here shown as a relay having a slow pickup characteristic.

The track battery l3 supplies energy to the rails of section 3T over either a front contact of the track relay ZTR or a front contact [ii of the timing reIayZTE. That is, when track relay 2TB, becomes deenergized, track relay 3TB, will also become deenergized so that signal 3 will indicate stop, and when relay 2TB is deenergized, relay 3TH, can be energized to cause signal 3 to display a restrictive proceed indication only ifthe timing relay 'ZTE has completed its operation.

The referance character 3AR designates a normally energized approach relay which is connected in series with the line circuits for section 4T and which is effective to initiate operation of the timing relay ZTE when section 4T becomes occupied. While relay 3AR, as here shown, will become deenergized only when section tiT'is occupied, the control for relay EAR, if desired, may be modified to include one or more sections to the rear of section 4T.

With the train K occupying section 2T so that both track relays ZTR and 3TB are deenergized and both signals 2 and 3 are displaying the stop indication, I shall assume that a following train enters section 4T so that track relay 4TH. be-

' comes released.

When track relay 4TR is released, approach relay 3AR will become deenergized, this relay having been previously energized over a circuit which passes from terminal B through relay 3AR, back point of contact 62 of relay 3I-IDP, relay 4LR, front contact 63 of track relay 4TB, back point of contact 64 of relay BLR, and back point of contact 65 of relay 3HDP to terminal C.

When relay 3AR is deenergized, the operation of timing relay 2TB will be initiated by a circuit which passes from terminal B through back point of contact 66 of relay ZHDP, back contact 6'! of track relay ZTR, relay ZTE, back contact 68 of approach relay 3AR, back point of contact 69 of track relay 3TB, back point of contact 10 of relay ZLR, and back point of contact ll of relay 2HDP to terminal C.

As soon as timing relay 2TE completes its operation so that its front contact 6! becomes closed, track relay 3TB. will become energized so that signal control relay 3LR will become energized to cause signal 3 to display a proceed indication. The circuit for relay SLR may be traced from terminal B at signal 2, through back point of contact 66 of relay 2HDP, relay BLR, front point of contact 69 of relay 3TR (which is now closed), back point of contact 16 of relay 2LR, and back pointl of contact H of relay ZHDP to terminal C.

The previously traced energizing circuit for timing relay Z'I'E will become opened when relay 3TR becomes energized. The relay 2TE, however, is provided with a holding circuit which passes from terminal B through back point of contact 66 of relay ZHDP, back contact 61 of relay ZTR, relay 2TE, front contact 12 of relay ZTE, and back point of contact H of relay ZI-IDP to terminal C. The holding circuit will maintain timing relay 2TE in its operated condition until such time as section 2T becomes unoccupied, whereupon the timing relay will return to its initial deenergized condition ready for the next operation.

It will be apparent that the following train will receive a restrictive proceed indication or a stop indication at signal 3 according as such train consumes more or less time, respectively, than the operating time of relay ZTE.

While the arrangement shown in Fig. 2 is illustrated and described as being applied to the first signal in rear of a signal displaying the stop indication, it is understood that a similar arrangement might be provided for any of the signals displaying other than the normal proceed indication. For example, the signal control relay 6LR for signal 6 might be controlled by a timing device, in such a manner that signal 6 would display the same indication as signal 5, when section 5T is occupied, and would display its usual less restrictive indication only if a train consumed a predetermined amount of time in section IT.

The modification shown in Fig. 3, illustrates a flashing device designated by the reference character FR and here shown as the usual and well-known flasher relay. The relay FR is controlled by a front contact 14 of the signal control relay LR so that the flasher relay FR is energized whenever the relay LR. is energized. The lower unit lamp LE is in turn controlled by front contact 14 of relay LR and by contact 15 of flasher relay FR so that the indication provided by that unit is a flashing light instead of a steady light. The modification shown in Fig. 3 may be applied to each lower unit of any or all of the signals shown if it is desired to provide a more distinctive indication.

From the foregoing description of the apparatus embodying my invention, it is apparent that I have provided simple and reliable apparatus for controlling a six-indication, five-block system of signaling wherein only direct current is utilized and wherein only three line control wires are required. Furthermore, my system may be modified to provide restrictive indications which may be changed to less restrictive indications if the speed of the trains is controlled properly, or the system may be modified to provide more arresting indications by flashing the lamps providing such indications.

Although I have herein shown and described only several forms of apparatus embodying my invention, it is understood that various changes and modifications may be made therein within the scope. of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. A railway signal system comprising; a first, a second, a third, a fourth, a fifth, and a sixth track section over which traffic normally progresses in the order named; a polarized line circuit for each section, a relay for each section, means controlled by a train occupying the sixth section effective to deenergize both the line circuit and the relay of that section, means then effective to deenergize the line circuit for the fifth section and to energize the relay for that section, means then effective to energize the line circuit for the fourth section in the reverse direction and to deenergize the relay for that section, means then effective to energize the line circuit for the third section in the reverse direction and to energize the relay for that section, means then effective to energize the line circuit for the second section in the normal direction and. to deenergize the relay for that section, means then effective to energize the line circuit for the first section in the normal direction and to energize the relay for that section, and signaling means controlled by the last mentioned line circuit and relay.

2. A railway signal system comprising; a first, a second, a third, a fourth, a fifth, and a sixth track section over which traflic normally progresses in the order named; a polarized line circuit for each section, a relay for each. section, means controlled by a train occupying the sixth section effective to deenergize both the line circuit and the relay of that section, means then effective to deenergize the line circuit for the fifth section and to energize the relay for that section, means then efiective to energize the line circuit for the fourth section in the reverse direction and to deenergize the relay for that section, means then effective to energize the line. circuit for the third section in the reverse direction and to energize the relay for that section, means then eifective to energize the line circuit for the second section in the normal direction and to deenergize the relay for that section, means then efiective to energize the line circuit for the first section in the normal direction and to energize the relay for that section, a signal for the sixth section caused to display the stop indication when the associated line circuit and relay are both deenergized, and signals one for each of the remaining sections and each caused to display a distinctive proceed indication in accordance with the condition of the associated line circuit and rey.

3. A railway signal system comprising; a first, a second, a third, a fourth, and a fifth track section over which traffic normally progresses inthe reverse direction to the order named; a polarized line circuit for each section, a relay for each section, means controlled by a train occupying the first section and eifective to deenergize both the line circuit and the relay for that section, means then efiective to deenergize the line circuit for the second section and to energize the relay for that section, means then effective to energize the line circuit for the third section in the reverse direction and the deenergize the relay for that section, means then effective to energize the line circuit for the second section in the reverse direction and to energize the relay for that section, means then effective to energize the line circuit for the first section in the normal direction and to deenergize the relay for that section, and a signal for the fifth section controlled by the line circuit and relay for that section and caused to indicate that the first section is occupied.

4. A railway signal system comprising; a first, a second, .a third, a fourth, and a fifth track section over which trafiic normally progresses in the reverse direction tothe order named; a polarized line circuit for each section, a relay for each section, means controlled by a train occupying the first section and effective to deenergize both the line circuit and the relay forthat section, means then effective to deenergiz'e the line circuit for the second section and to energize the relay for that section, means then efiective to energize the line circuit for the third section in the reverse direction and to deenergize the relay for that section, means then effective to energize the line circuit for thesecond section in the reverse direction and to energize the relay for that section, means then eflfective to energize the line circuit for the first section in the normal direction and to deenergize the relay for that section, a signal for the first section caused to display the stop indication when the associated line circuit and relay are both deenergized, and signals one for each of the remaining sections and controlled by the associated line circuits and relays, said remaining signals each being caused to display a distinctive and a successively less restrictive indication in accordance with their numerical order. i

5. In combination, two adjacent sections of railway track each having a track circuit in cluding a track relay, a line circuit for the rear section including a front contact of each of said track relays, another line circuit for the rear section including a front contact of the track relay for that section, a signal for the forward section, a pole changing relay controlled by said signal for governing said first line circuit, means including another relay governed by said signal for controlling said second line circuit, a line relay connected to said second line circuit, and a signal for the rear section controlled jointly by said line relay and by said first line circuit.

6. In combination, a plurality of successive sections of railway track, each such section having a track circuit including a track relay, a plurality of signals one for each section and each such signal comprising a first unit and an auxiliary unit, means for controlling each first unit in accordance with traffic conditions in advance of the associated signal, a contact for each section which is closed only when the first unit of the associated signal is displaying its least restrictive indication, a signal control relay for each section for controlling the auxiliary unit of the associated signal, and two circuits for each signal control relay, each circuit including a front contact of the track relay for the associated section, one circuit including a back contact of the signal control relay for the section next in advance and the other circuit including a front contact of the signal control relay for the section next in advance as Well as said contact for said advance section.

'7. In combination, a forward section and a rear section of railway track, a signal for each section and each signal comprising two units, a relay for controlling one unit of the signal for the forward sectiomsaid relay being energized under certain traffic conditions in advance of said signal and being deenergized under other trafiic conditions in advance of said signal, another relay for controlling one unit of the signal for the rear section, one circuit for energizing said other relay including a back contact of said first relay, and another circuit for energizing said other relay including a front contact of said first relay.

8. In combination with a stretch of railway track comprising a plurality of track sections, a source of current and a track relay for each section, a signal for each section comprising a first and a second indication unit, a signal control relay for each section for governing the indication displayed by the second unit of its associated signal, means associated with each of said sections and including the associated track relay for governing the indication displayed by the first unit of its associated signal, contacts operably governed by the first unit of each signal, and means for controlling each signal control relay governed by the contacts of the signal for the section next in advance as well as by said signal control relay for said advance section.

9. In combination with a stretch of railway track comprising a plurality of track sections, a source of current and a track relay for each section, a signal for each section comprising a first and a second indication unit, a signal control relay for each section for governing the indication displayed by the second unit of its associated signal, means associated with each of said sections and including the associated track relay for overning the indication displayed by the first unit of its associated signal, a pole changing relay governed by the first unit of each signal and by the associated signal control relay, and means for controlling each signal control relay governed by the pole changing relay of the signal for the section next in advance as Well as by said signal control relay for said advance section.

10. In combination, a stretch of railway track divided into a plurality of track sections each having a track circuit including a track relay, said plurality of sections including an occupied section and five successive sections to the rear of such occupied section, a signal for each section and each such signal comprising a first unit capable of displaying several distinctive indications and a second unit capable of displaying one indication or no indication, and means governed by said track relays and including three line wires for each section for controlling the two units of each signal in such a manner that one indication is displayed by the first unit of the signal for said occupied section as well as by the first unit of the section first in rear, another indication is displayed by the first units of the signals for the second and third sections in rear, a different indication is displayed by the first units of the signals for the fourth and fifth sections in rear, and an indication is displayed by the second unit of the signal for the section first in rear of the occupied section as well as by the second units of the signals for the third and fourth sections in rear.

11. A railway signal system comprising a stretch of railway track divided into a plurality of track sections, a plurality of signals one for each section and each such signal comprising a searchlight signal mechanism and an auxiliary lamp, means for governing each signal in such manner that when a particular section is occupied by a train the mechanism of the signal for the occupied section and the mechanism of the signal for the first section to the rear of such occupied section are both deenergized, the mechanisms of the signals for the second and third sections to the rear are supplied with current of reverse polarity, the mechanisms of the signals for the fourth and fifth sections to the rear are supplied with current of normal polarity, and the lamps of the signals for the first and third as well as the fifth sections to the rear of the occupied section are energized.

12. In combination, three successive sections of railway track including a forward section and a rear section as well as an intermediate section, a track circuit including a track relay for both the forward section and the rear section, a track relay connected across the rails of the intermediate section, a source of current, means including a front contact of the track relay for the forward section for connecting said source of current to the rails of the intermediate section, a timing device, means controlled by the track relays of each section for initiating the operation of said timing device when the forward section and the rear section both become occupied, a circuit for connecting said source of current to the rails of the intermediate section when said device completes its operation, and a signal for the intermediate section governed by the track relay for that section.

slow acting device, means for initiating the operation of said device when a train is approaching the signal for the rear section provided the forward section is then occupied by another train;

current connected across the rails of the rear: section through a front contact of the track relay for the forward section, a signal for each section controlled by the track relay for that section, a normally deenergized slow acting relay, a circuit including a back contact of both track relays for energizing said relay when a train is approaching the signal for the rear section, a circuit including a front contact of said slow acting relay and a back contact of the track relay for the forward section for holding said relay in its energized condition, and means including a front contact of said slow acting relay for connecting said other source with the rails of the rear section.

15. In combination, three successive sections of railway track including a forward section and a rear section as well as an intermediate section, a track circuit including a track relay for both the forward section and the rear section, a track relay connected across the rails of the intermediate section, a source of current, means including a front contact of the track relay for the forward section for connecting said source of current to the rails of the intermediate section, a timing device, means controlled by the track relays of each section for initiating the operation of said timing device when the forward section and the rear section both become occupied, means for supplying energy to the rails of the intermediate section when said device completes its operation, and a signal for the intermediate section comprising a first unit controlled by the track relays for the intermediate section and the forward section and a second unit controlled by the track relay for the intermediate section.

16. In' combination, three successive sections of railway track including a forward section and a rear section as well as an intermediate section, a track circuit including a track relay for both the forward section and the rear section, a track relay connected across the rails of the intermediate section, a source of current, means including a front contact of the track relay for the forward section for connecting said source of current to the rails of the intermediate section, a timing device, means controlled by the track relays of each section for initiating the operation of said timing device when the forward section and the rear section both become occupied, means for supplying energy to the rails of the intermes diate section when said device completes its operation, and a signal for the intermediate section comprising a mechanism and a lamp, said mecha-- nism controlled by the track relays for the intermediate section and the forward section and said lamp controlled by the track relay for the intermediate section.

1'7. In combination, three successive sections of railway track including a forward section and a rear section as well as an intermediate section, a track circuit including a track relay for both the forward section and the rear section, a track relay connected across the rails of the intermediate section, a source of current, means including a front contact of the track relay for the forward section for connecting said source of current to the rails of the intermediate section, a timing device, means controlled by the track relays of each section for initiating the operation of said timing device when the forward section and the rear section both become occupied, means for supplying energy to the rails of the intermediate section when said device completes its operation, and a signal for the intermediate section comprising a first unit and a second unit, said two units controlled by the track relays for the intermediate section and the forward section in such a manner that said signal is caused, to indicate a more restrictive or a less restrictive indication according as the track relay for the intermediate section is deenergized or energized respectively.

18. In combination, a stretch of railway track divided into a plurality of sections, a signal for one of said sections comprising two units, one unit being a mechanism capable of displaying three different indications and the other unit being a lamp which in conjunction with particular indication of the first unit causes the display of a less restrictive or a more restrictive indication according as said lamp is lighted or extinguished respectively, means for causing said other unit to become extinguished when a particular section in advance of said signal is occupied, a timing device, means for initiating the operation of said timing device when another train occupies a particular section in rear of said signal if said advance section is also occupied, and means elTective to light said lamp when said timing device completes its operation.

19. In combination, a stretch of railway track divided into a plurality of sections, a signal for one of said sections comprising two units, one unit being a mechanism capable of displaying three different indications and the other unit being a lamp which in conjunction with a. particular indication of the first unit causes the display of a less restrictive or a more restrictive indication according as said lamp is lighted or extinguished respectively, means for controlling said mechanism in accordance with traffic conditions in certain sections in advance of said signal, a line relay controlled by traffic conditions in such advance section, a flasher relay controlled by said line relay, and a circuit for said lamp controlled by said line relay and. including contacts of said flasher relay.

20. In combination, a section of railway track, a signal for said section comprising two units, one unit being a mechanism responsive to the polarity of the current supplied thereto and the other unit being a lamp, a polarized line circuit connected to said mechanism and reversibly goveined by traffic conditions in advance of said signal, a flasher relay for controlling said lamp, and means including another line circuit for controlling said flasher relay in accordance with traflic conditions in advance of said signal.

EARL M. ALLEN. 

